SWRP Diversion Permit Application FAQs

Read our Frequently Asked Questions (FAQs) to learn more about Aquarion's proposal to increase the transfer of water from the Greater Bridgeport System to the Southwest Fairfield County Region (SWFC). The increased capacity of the Southwest Regional Pipeline (SWRP) will provide supply resilience, reduce drought risk, and enable Aquarion to make ecological reservoir releases in compliance with new regulations.

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Aquarion operates separate public water systems in Greenwich, Stamford, Darien and New Canaan. Because these are interconnected and share sources of supply, Aquarion performs water resource planning for the four systems as a single region: the Southwest Fairfield County Region (SWFCR).

map of Southwest Fairfield County Region water supply sources

The Southwest Fairfield County Region (SWFCR) is supplied by the Putnam and Mianus Water Treatment Plants in Greenwich, the Stamford Water Treatment Plant in Stamford and an interconnection that transfers water into the region from Aquarion’s Greater Bridgeport System. Water for the treatment plants in Greenwich and Stamford comes from separate systems of multiple reservoirs. There is also a small well in Darien (the Rewak Well) and an infrequently used well in Stamford (the Wire Mill Well).

map of Southwest Fairfield County Region water supply sources

The interconnection that brings water to the Southwest Fairfield County Region (SWFCR) from the Greater Bridgeport area is referred to as the Southwest Regional Pipeline (SWRP). It was constructed in phases after the 1980s drought and has been operational in its current form since the early 1990s.

map of Southwest Fairfield County Region

Connecticut Department of Energy and Environmental Protection (DEEP) regulations require a diversion permit to withdraw more than 50,000 gallons per day (gpd) from a surface water or groundwater or to transfer more than that amount between “service areas."  The Southwest Regional Pipeline (SWRP) transfers water between service areas and therefore requires a permit.  Withdrawals from the sources of supply that provide water to the SWRP are separately authorized by DEEP and withdrawals will remain below their currently authorized limits.

The current Southwest Regional Pipeline (SWRP) diversion permit authorizes a maximum daily transfer of up to 7.26 million gallons per day (mgd) from the Greater Bridgeport service area to the four towns in the Southwest Fairfield County Region (SWFCR). This permit was issued in 2003 and expires on June 30, 2023.

This application requests to increase the authorized maximum daily capacity of the Southwest Regional Pipeline (SWRP) to 14.2 mgd for 25 years.

The Connecticut Department of Public Health (DPH) requires that water systems maintain an adequate source of supply to meet their projected needs, typically defined as 15% more supply than projected demand. The Southwest Fairfield County Region (SWFCR) currently has less than 10% more supply than demand and is projected to have inadequate supply in the future based on growth projections for the four communities. The available water will be reduced further in 2029 with the implementation of regulations that require increased reservoir releases for ecological protection.

For these reasons Aquarion is proposing to increase the transfer of water from the Bridgeport System to the SWFCR. The increased capacity of the Southwest Regional Pipeline (SWRP) will provide supply resilience, reduce drought risk, and enable Aquarion to make ecological reservoir releases in compliance with the new regulations.
Conservation is critical to managing water resource for the Region. Aquarion implemented two-day per week irrigation restrictions in the Region that have helped reduced water demands while providing for adequate landscape irrigation. Continued vigilance complying with these restrictions will reduce the amount of water transferred through the Southwest Regional Pipeline (SWRP) and will potentially help defer the infrastructure improvements needed to attain the requested pipeline capacity.

Water for the Southwest Regional Pipeline (SWRP) comes from the Hemlocks Reservoir System and Treatment Plant in Weston, Easton, and Fairfield; and the Canal Street and Coleytown Wellfields in Westport. Incremental supply for the Pipeline comes primarily from the reservoir system.

The Greater Bridgeport System supplies interconnection to Aquarion’s water systems in Newtown and Ridgefield in addition to the Southwest Regional Pipeline (SWRP). As demonstrated in the permit application, with reactivation of the Housatonic Wellfield in Shelton the Greater Bridgeport System has adequate supply to support these interconnections in addition to meeting the projected needs of the Greater Bridgeport area while also making increased reservoir releases to enhance downstream ecology.